Chop apples into 1/4 inch pieces. Set aside. In a large mixing bowl add cream cheese, sugar, and cinnamon. Beat together. Fold in apples until mixed in.
8 ounces cream cheese, 1/2 cup granulated sugar, 2 large granny smith apples, 1 teaspoon cinnamon
Slice the croissants down the center to form a pocket, making sure not to pierce through. Spoon ~2 Tablespoons of the cream cheese mixture into each croissant.
6-7 large croissants
Butter a 12x8 baking dish. Arrange the croissants facing up.
Whisk together the milk, eggs, and vanilla extract.
3 large eggs, 1 cup milk, 2 teaspoons vanilla extract
Pour the custard mixture over the croissants. Set aside.
In a bowl add the flour, oats, brown sugar, salt, and butter. Cut the flour mixture with a pastry cutter into the mixture until it resembles coarse crumbs. Or, use a hand blender to incorporat the ingredients.
1/2 cup all-purpose flour, 1/2 cup rolled oats, 1/4 cup packed light brown sugar, 1/2 teaspoon kosher salt, 5 Tablespoons cold unsalted butter
Sprinkle the oat crumble over the croissants in the baking dish. Cover with aluminum foil, and refrigerate overnight.
When ready to bake, let the french toast sit out for 30 minutes to come to room temperature.
Preheat the oven to 375 degrees Fahrenheit.
With the foil still covering the dish, place the french toast in the oven for 20 minutes. Remove the foil, and bake for an additional 10- 15 minutes or until top is golden brown. Serve immediately.